1 // Copyright 2009 The Go Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style 3 // license that can be found in the LICENSE file. 4 5 package math 6 7 // Modf returns integer and fractional floating-point numbers 8 // that sum to f. Both values have the same sign as f. 9 // 10 // Special cases are: 11 // Modf(Inf) = Inf, NaN 12 // Modf(NaN) = NaN, NaN 13 func Modf(f float64) (int float64, frac float64) 14 15 func modf(f float64) (int float64, frac float64) { 16 if f < 1 { 17 switch { 18 case f < 0: 19 int, frac = Modf(-f) 20 return -int, -frac 21 case f == 0: 22 return f, f // Return -0, -0 when f == -0 23 } 24 return 0, f 25 } 26 27 x := Float64bits(f) 28 e := uint(x>>shift)&mask - bias 29 30 // Keep the top 12+e bits, the integer part; clear the rest. 31 if e < 64-12 { 32 x &^= 1<<(64-12-e) - 1 33 } 34 int = Float64frombits(x) 35 frac = f - int 36 return 37 } 38
